Sanitary rotary pump



March 12, 1940.

A. w. DIETZEL 2,193,273 SANITARY ROTARY PUMP Filed Jan. 31, 19:58 2 Shets-Sheet 1 Fig. '2.

INVENTOR ALEXANDER w. DIETZEL immwm ATTORNEYS March 12, 1940. A. WLDIETZEL 2,193,273

' SANITARY ROTARY PUMP Filed Jan. 31, 1938 2 Sheeis-Sheet 2 .Fig. 4,.

INVENTOR oar: W DIETZEL.

ALW

IAITORIJEYQ I Patented Mar. 12, 1940 I UNITED STATES sam'mnr ROTARY PUMP l Alexander W. Dietzel. Waukesha, Wis., assignor to Waukesha. Foundry Company, Waukesha,

Wia,

a corporation of Wisconsin Application January 31, 1938, Serial No. 187,792

5 'Claims.

My invention relates to improvements in sanitary rotary pumps, with particular reference to pumps for handling milk and other liquiform foods subject to requirements for a thorough cleansing of all parts after each operation.

My objects are to facilitate complete separation of parts for separate cleansing after each pumping operation; to reduce the number of parts to a minimum; to eliminate all interior packings; to not only provide for complete separation of lubricated driving mechanism from the pumping mechanism, but to provide exterior packing devices for the pump shafts which may be released for separate removal from the exterior side of the pump casing upon withdrawal of the pump piston and shaft members, and which can be reassembled with precision when said shaft members are restored.

A further object is to provide a rotary pump having smooth surfaced internal contours, all of which are easily accessible for cleansing purposes, and none of which are provided with joints or crevices in which infected material or foreign matter may lodge.

Heretofore numerous attempts have been made to provide rotary pumps for liquiform foods which will satisfy oiilcialrequirements, directed not only to the possibility of sanitation, but to facility in obtainingcomplete sanitation and thorough inspection. Many problems-some of them quite obscure-have been encountered, and so far as I am aware no satisfactory pump of rotary type has heretofore been produced, which meets re quirements for sanitation.

I believe my rotary pump satisfies the requirements of milk inspectors and sanitary boards dealing with dairy products, particularly those requirements which specify that such parts must be free from joints, crevices, and passages which cannot be readily separated, inspected, and cleansed with such facility that regulations ensuring complete sanitation can be reasonably enforced. My improved pump has met with gen eral approval as satisfying these requirements.

Therefore, it is my general object to completely solve the aforesaid problems and provide a. rotary pump which will thoroughly satisfy all require ments for sanitation and thorough speedy inspection.

In the drawings:

Figure 1 is a front elevation of my improved pump, with the cap removed, preparatory to withdrawal of the pistons and associated shaft sections.

shaped pistons l8 and flow being dependent ton rotation. The

Figure 2 is a sectional view drawn to line 2-2 of Figure 1, and showing the cap in place.

Figure 3 is an enlarged detail sectional view of one of the packing boxes and an associated fragment of the pump casing and shaft.

Figure 4 is a view similar to,Figure 1, with the pistons and shafts removedfand with a portion shown in section, through one of the ports.

Figure 5 is a view of the cap as seen from the inner side.

Figure 6 is a sectional view drawn generally to line 6-6 of Figure 4.

Figure 7 is a view of the removable parts associated with one of the pump cylinders, showing the same in separated relationship.

Figure 8 is a view similar to Figure 3, showing a slight modification;

Like parts are identified by the same reference characters throughout the several views.

My improved pump casing comprises but two 20 separable parts, which may respectively be aptly termed the supporting back wall member ID and the front wall or cap I I, the latter being normally secured to the back wall by screws l2, having thumb nuts or operating pieces I3. The screws i2 pass through apertures in the cap and enter threaded sockets in the back wall member H), as clearly shown in Figure 2. l

The front face of the back wall member I 0 is cavitated to provide a pair of intersecting cylindrical cavities l6 and I1, whichreceive crescent l9 of a well-known type, operative upon the displacement principle, to alternately draw liquiform material into the respective lobes through one of the ports 22 (or 23) and expel it through the other, the direction of upon the direction of pisperiphery of each piston is adapted to enter. an arcuate socket in the hub of the other piston to sub-divide the lobes into suction and pressure cavities, as is customary in pumps of the described type.

The piston l8 has its hub 25 mounted upon the shaft 26. The piston I 9 has its hub 21 mounted upon the shaft 28, and the hubs 25 and 21 are journaled in bearing sockets 29 and 30 formed in the interior face of the cap ll,

Each of the shafts has a portion of larger diameter than the hub receiving portion which extends through an aperture in the back wall member In, bushings 33 being preferably employed for these apertures. The rear ends of these shaft members are of less diameter than the portions received in the bushings 33 and extend to the exterior through suitable packing boxes.

tions 48 on the back Their exposed ends are connected by coupling sleeves 35 with driving shafts 55 and 51 mounted in a gear chamber 35. In the construction shown. the shaft 55 serves as a driving shaft and transmits motion through the gear wheels 55 and 45 to the shaft 31. The sleeves 55 are preferably keyed to both shafts of the respective pairs and i also connected with the driving shafts by cross pins 52. whereby the sleeves are retained in position on the driving shafts while allowing the pump shafts to be withdrawn axially through the pump casing when the cap II is removed. The gear casing and pump casing are spaced from each other, but are detachably connected with each other by bolts 45 and 55, the bolts 55 being socketed in spacing sleeves 51, preferably formed integrally with one wall of the gear casing and abutted against corresponding socketed projecwall 0.

The back wall I is also provided with stud-like projections 50 which are exteriorly threaded to receive the caps and provide packing boxes through which the pump shafts extend. Within each of these packing boxes the associated shaft is provided with a loose collar 55 having an annular flange 55, between which and the associated shaft a packing collar 51 may be received.

This collar 51 is non-metallic, a non-porous composition of rubber and other materials being preferably employed. So-called grease or acid proof composition materials are commercially available for such purposes.

The collars 51 are compressible, and are held against the collars 55 by compression springs 55, each of which has one end seated against an. associated shaft shoulder 5 l The other end seats: against a ring 52 interposed between the spring and the compressible collar 51.

The external diameters of the coiled compression springs 50 exceed the internal diameters of the bushings 33, and, therefore, when the pump cap II is removed, the pistons and associated shaft sections may be withdrawn without disturbing the springs 50 and the packing rings or collars. After so withdrawing the shafts, the caps 5| may be unscrewed to allow the packing collars and springs to be withdrawn in the space between the pump and the gear case, whereupon all of the parts may be separated for cleansing purposes, as indicated in Figure '1.

Each of the caps 5| has a ground annular face 55 to receive the thrust of the collar 55, and the threaded portion of the cap may engage a compressible packing gasket 55 between it and an annular surface of the member "I surrounding the stud-like projection 55. Therefore, any liquidescaping into the packingbox from the pump cavity will be prevented from following the ed rings 52 and completely fill the spaces between shaft or otherwise leaving the packing box.

The compressible packing collars 51 expand radially under the pressure of the spring actuatthe flanges 55 and the shafts with bindin pressures in all directions.

Liquid in-the packing boxes will be prevented from passing around the collars 55 by reason of-the ground Joints between these collars and the packing box caps 5|. The contacting faces of the collars 55 and the cap screws 5| are narrow in the radial dimensiomand the cap screws are not in contact with their associated shafts. Also, liquid will be prevented by the gaskets 55 from following the cap screws.

The packing box caps or capscrews 5| are prevented from rotating with the shaft for the reason that the friction of these caps along the I screw surfaces and upon the packing rings 55 is much greater than the friction of the collars 55 on their ground annular faces 55. But the collars 55, 55 and the associated springs 50 rotate with the shaft inasmuch as their combined pressure and friction upon the shafts and upon each other is tion at the ground joints 55. Therefore, wear will occur only at these ground joints 55.

In Figure 8 the cap screw 5la has a slightly conical surface at 15 and a gasket 1| is located between this surface and the conically tapered end of the tubular stud 5M. The tapered end of this stud has a projecting annulus 11 which provides anchorage for the gasket 1|. If such gnaskets are used, gaskets 55 may be dispensed From the foregoing description it will be observed that the pump casing comprises but two members, and that each piston and shaft assembly is permanently connected as a unit. There are no interior packings, joints or crevices in which unsanitary material may lodge, and all working surfaces are completely exposed to view when the casing cap is removed and the piston and shaft units withdrawn.

Also, these piston and shaft units may be withdrawn without disturbing the exterior packing rings and springson the outer face of the supporting casing member. When the shafts are withdrawn, the springs which are normally seated against the shaft shoulders become seated against the supporting wall of the casing, whereby the packing rings are left undisturbed pending removal of the packing box caps. L

With this construction the packing box caps may be removed from the outer sideof the supporting wall of the casing, separately cleansed, and restored to their normal positions after cleansing the interior surfaces of the packing boxes and before re-inserting the shafts through the supporting wall from the front side. When the shafts are thus re-inserted there will be an additional compression of the springs when the casing cap is being screwed into place, because the shaft shoulders will then push the springs out of contact with said supporting ;wall so that they may freely rotate with their associated shafts. v

I claim:

1. A sanitary rotary pump having a two piece casing, comprising a supporting member and a manually removable cap member, unitary piston and shaft elements each shaft element having smooth surfaced bearings in the supporting member with its power receiving portion projecting exteriorly and reduced in diameter, the other shaft end being normally covered by the cap member, packing, rings on the exterior portions of'theshafts, ring retaining packing boxes removably'secured to the supporting member and subject to thrust of the packing rings, compression springs seated between portions of the protruding ends of said shafts and the packing rings, said springs being of larger diameter than the shaft apertures in the casing member and adapted to seat against said member when the shaft elements are withdrawn, and gaskets between the packing boxes and the supporting casing member cooperative with the packing rings for normally sealing the packing boxes against the escape of fluid from the pump. v

2; Asanitary rotary pump having a two piece casing, comprising a supporting member and a materially greater than the fricmanually removable cap member, unitary piston and shaft elements having shaft ends extending through the supporting member and the other shaft ends normally covered by the cap member, packing rings on the exterior portions of the shafts, ring retaining packing boxes removably secured to the supporting member and subject to thrust of the packing rings, compression' pump shafts and pistons forwardly removable from a supporting wall, the combination with such supporting wall of driving mechanism spaced from the rear face of the supporting wall, packing boxes on the rear face of said wall and through which the pump shafts normally extend, sets of packing .rings in said boxes normally in frictional pressure contact with an associated shaft, and compression springs normally interposed between the boxes and the bearing portion of the shaft in the back wall, said springs being adapted for engagement with the back wall when the shaft is withdrawn.

4. In a sanitary rotary pump 'for liquiform foods, the combination with a two part casing, including a supporting wall and a removable cap wall, of a pump shaft having a bearing portion mounted in the supporting wall with one end journalled in the cap wall and its other end portion projecting and provided with an annular shoulder exterior to the casing and a reduced power receiving portion beyond the shoulder, a packing unit mounted on the reduced portion and including relatively movable metal housing members having between them an impervious compressible packing ring adapted to be forced into contact with the shaft by pressure exerted upon one of the housing members, a compression spring interposed between said housing member and the shaft shoulder, and a packing box adjustably connected with the supporting casing member and provided with an annular thrust receiving bearing for the other housing member of the packing unit, said packing unit being rotatable with the shaft, and said casing wall and packing box-being adapted to support said unit substantially in its operative position when the shaft is withdrawn.

5. In a sanitary rotary pump combination, a supporting wall, free from joints and apertures other than shaft apertures, a detachable front wall free from joints and apertures, piston and shaft assemblies normally ,held in place by the front wall, with the shafts extending from the front wall through the supporting wall and reduced in diameter at the other side thereof, and packing members normally mounted upon said reduced end portions of the shafts in resilient forwardly exerted thrust relation thereto and distant from the supporting wall, and normally stationary means for enclosing said packing mem-, bers in frictional thrust receiving relationship thereto.

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